Colloid cyst
- A well-demarcated T1-hyperinse lesion in the third ventricle at the level of the foramina of Monro.
- 55-year-old patient presented with bladder dysfunction and unsteadiness.
- CT showed a 7 mm hyperdense lesion filling the foramen of Monro and marked enlargement of the ventricles.
- There was very little periventricular oedeam, and so the appearances suggest chronic, compensated, ventriculomeagly (rather than acute hydrocephalus).
- A 20-year-old patient presented with an acute onset severe headache and reduced GCS.
- MRI showed a non-enhancing cyst near the foramina of Monro and acute hydrocephalus.